September 2017
Alright, no matter what I do the game crashes after lighting the second signal fire and during the cutscene that follows.
I'm on a Mac, playing via Origin.
It's Aveline's personal quest in Act 2, called The Long Road.
Did you try repairing the game in the Origin client? You can do this by right clicking* the game in the Origin library and selecting the repair option.
* Instead of right clicking, you can do whatever your trackpad perceives as a right click.